Method for multiplying the frequency of electric currents.



l. SHOENBERG.

METHOD FOR MULTIPLYING THE FREQUENCYOF ELECTRIC CURRENTS.

APPLlCATlON FILED DEC.27,1917.

1 ,26 9,0 1 1 Patented June 11, 19,18.

3 SHEETS-SHEET 1- Fig-J.

H a; F5 21) i M Fig.2.

l. SHOENBERG.

METHOD FOR MULTIPLYING THE FREQUENCY OF ELECTRIC CURRENTS.

' APPLICATION FILED DEc.27,1917.

1,26 9,01 1 Patented June 11, 1918.

3 SHEETSSHEET 2.

l. SHOENBERG. METHODFOR MULTIPLYING' THE FREQUENCY OF ELECT-RIC CURRENTS.

APPLICATION FILED DEC.2,7, 1917- Patented June 11. 1918.

3 SHEETS SHEET 3- Strand, London, England, have invented av UNITED STATES PATENT OFFICE.

ISAAC SHOENBEBG, OF LONDON, ENGLAND, ASSIGNOR TO MARCONI WIRELESS TELE- GRAPH COMPANY OF AMERICA, JERSEY.

OF NEW YORK, N. Y., A CORPORATION OF NEW METHOD FOR IULTIPLYING THE FREQUENCY OF ELECTRIC CURRENTS.

Specilcation of Letters Patent. Patented J 11119 11 1918.

Application filed December 27, 1917. Serial No. 209,197.

To all whom it may concern:

Be it known'that' I, Isaac Snonrmmzo, a Russian subject, residing at Marconi House,

new and useful Improved Method for Multiplying the Frequency of Electric Currents, of which the following is a specification.

This invention relates to a method of multiplying the frequency of electric currents. This invention is' based on the following principle :If one of the mains from a source of alternating current includes a coil upon an ironcore in which are no air gaps orat most ve small ones, and which has a second winding in circuitwith a source of direct current, and a choldng coil with anopen core, the 'curves for the current and voltage in the mains will possess the peculiarity that the amplitude on one side is much larger than that on the other, while that portion of the period which corresponds to the larger amplitude is smaller than the portion corresponding to the smaller amplitude, the ratio of the one portion to the other being a function of the ampere turns of the two windings.

Each phase of a supply of n phases is therefore treated in this way, so arranging the ampere turns of the windings that the said ratio shall be equal to l/n, and the n currents are combined, thus obtaining a current of a frequency n times that of the fundamental.

showing the connections and arrangementof When n is large, in order to avoid the use of a multiphase generator of the ordinary type which might be inconvenient, a phase transformer may be us'ed consisting of an iron core, in which a rotating field is created, and around which coils are spaced in such a way .as to get'the necessary phase difl'erenoe, as described in my application for Patent No. 124251, lodged 7th. October, 1916.

This invention is illustrated by the accompanying diagrams. Figure 1 shows the arrangement of apparatus for producing from an alternator a. current with a curve such as is shownfin Fig. 2, while the thick line in Fig. 3 represents the current obtained from a four phase supply and having four times its frequency.

4: and 5 are diagrammatic views continuous current source B.

apparatus for producing the relation of current waves shown in Fig. 3, the phases being in series and. in parallel respectively in Figs.

4 and 5.

In Fig. 1, A is a source of alternating current, C is an iron core with no gaps, or with very small ones, and on this core are placed two windings; the one Dis inserted 'in one of the mains from A, while the other F is connected to a source Bof direct current through an adjustable resistance R and a choking coil G having an open core so that the core (1 can be saturated The curves for the current or voltage between the points M, N, of the main will be of thefform shown inFig. 2. In this figure a 0 corresponds to a full period, the amplitude -on one side is much, larger than on the other andsthe part a b is'much smaller than half a period. The ratio 1/n:a 6/11 0 is a function of the ratio'of the ampere turns in Dead F.

If a similar arrangement is therefore introduced into each of the phases of a supis shown at A in both Figs. 4; and 5, A

being a three phase alternator. Machine A is connected to a phase transformer having a circular core after the manner of British Patent No. 14,423 of 1915, the primary coils being omitted for purposes of illustration.

I I, I and I are four'secondary coils on the said core spaced 90 apart. Owing to the rotating field produced in said core by the primary currents, said secondary coils produce currents ninety degrees apart. In

one lead of each of the secondar coils are choking coils D, D, D and respectively, wound on the corres ending closed cores C, C, C and C. T e cores, of the choldiig coils are saturated by current in coils F, F and F, sup lied by the urrent regulating resistance R and choking coil G are in series with coils F, F, F and F. When the current "in coils F F, F and F is without the H ap arat o for increasing quency of a hase current comprisicoils having iron cores of low reluctance co nected into one load of each phase, winding ror continuous current on each o cores, and for supplying cu;

said winding, the ratio lo. co ous current ampere turns and the sit current ampere turns being such t no current wave of each phase is increased amplitude and decreased in duration on one side of the zero line to such entent the portion of increased amplitude is an integral fraction of the fundamental frequency, the phases being directly connected in such manner that the portions of the current waves of increased amplitude all lie on the same side of zero line.

2, An apparatus for increasing the fre quency of a multiphase current comprising a coil having an iron core of low reluctance connected into one lead of each phase a winding for continuous current on each of said cores, means for supplying current to said windings, and a choking coil having a core with open magnetic circuit in series with each of said windings, the ratio leetween the continuous current ampere turns and the alternating current ampereturns being such that the current wave of each phase is lncreased in amplitude and decreased in duration on one side of the zero line to such extent that the portion of increased amplitudejs an integral fractioniof the fundamental frequency, the phases being directly connected in such manner that the portions of the current waves of increased amplitude all lie on the same side of the zero line.

3. The method of obtaining a relatively high frequency current from n currents of different phase having a common lower frequency, which consists in increasing the amplitude and decreasing the duration of one part of the current wave of each of said currents and directly combining the resulting currents with non-magnetic connections to give a single alternating current of n times the frequency of the original currents.-

4. The method of obtaining a relatively high frequency current from a plurality of currents of difiercnt phase havin a common lower frequency consisting in de orming the wave shape of each phase in such' manner as to increase the amplitude and decrease the duration of the part of the wave on one side of the zero line as compared to the other part, so that the portions of increased reduced to i cycle and connecting the portions of the currents ed amplitude all lie on the same zero line in immediate succes i method of obtaining a relatively quency current from of different phase haying requency, which consists in dee wave shape of said on ner as to increase n dole L1 M 13 U 1. .2 case the duration or the cart or $1.3

ie other part, and directly a the deformed waves to give a cur rent of increased frequency.

d. The. of obtaining a ti I frequency current from a plurality 3L f lower cc-mto a source of continuous current for satultd rating the core, the phases being directly connected and the ratio of continuous current ampere turns to alternating current ampere turns being such that the resulting frequency is equal to the original frequency 185- multiplied by the number of phases.

8. An apparatus for increasing the frequency of a multiphase alternating current comprising in combination a coil connected into each phase of said source, saturated 11! cores for said coils of low magnetic reluct ance, and a winding for each core connected to a source of continuous current for saturating the core, the number of phases and coils as well as the ratio of the continuous current and alternating current ampere turns being so arranged as to enable the phases to be directly added and to give the desired multiple of the fundamental frequency.

9. The method of increasing the frequency of a multiphase current of sine wave shape, which consists in deforming the wave said portions of increased amplitude all lie on one side of the zero line in immediate succession with their zero points substantially coinciding and the resulting current Wave is substantially of equal amplitude on 5 both sides of the zero line and is substantially of sine form, and so that the frequency of'the resulting current isequal to the original frequency multiplied by the number of phases.

In testimony that I claim the foregoing 10 as my invention, I have signed my name this tenth day of December, 1917.

ISAAC SHOENBERG. 

